The United States and England are both ____________countries.
Scientists have reached the disturbing conclusion __________ the amount of the solar energy reaching the Earth's surface has been gradually falling.
Such a grammar mistake is __________ among the beginners of English study.
A person's __________ body temperature is about 37℃.
The program, __________ at improving the students' ability of listening and speaking, will surely be a success.
He didn't answer, with his gun __________ at David.